A DC to 1-GHz differential monolithic variable-gain amplifier

A monolithic bipolar variable-gain amplifier with 25-dB maximum differential gain and over 30 dB of gain-control range operating in the DC to 1-GHz frequency range is described. The circuit has a 9.3-dB noise figure from a 50 Omega source, an output third-order intercept of +13.5 dBm at high gain, and an input third-order intercept of +6 dBm at low gain. The gain varies linearly as the gain-control voltage varies from 0 to 1 V and the gain is insensitive to supply and temperature variations for a given gain-control setting. Power consumption is 225 mW from a single 5-V supply.<
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